Towing Performance Mods

03envoy

Original poster
Member
Dec 25, 2011
537
Hello,
After many test with my I6 Envoy, I will not be towing with this vechical anymore, That is unless you guys can give me some Advice on helping the Envoy Increase power.... I know about the Pcmforless tune, but I am holding off on that. I have Z71's which help with weight. What have you done to your I6????:biggrin:
Thanks,
Trent
 

Me007gold

Member
Nov 20, 2011
1,106
What are you trying to tow? and what Gear do you have? Everything I've read makes these things seem like fairly good tow vehicles.
 

MrDJ

Member
Dec 4, 2011
180
Waxahachie, TX
I haven't done any modifications to affect performance and I tow a 2 ton trailer regularly with no problems at all. What are you trying to pull?
 

03envoy

Original poster
Member
Dec 25, 2011
537
About 1200lbs, Two Sleds.
 

mwking

Member
Dec 7, 2011
9
1200lbs for the sleds, how much for the trailer? Open trailer or enclosed? I tow two sleds in an enclosed trailer with my Trailblazer and it dosen't break a sweat. It's a narrow inline trailer, so tucks in behind the truck without a lot of wind resistance. A side by side enclosed trailer and a strong head wind will slow you up, but no different than towing a travel trailer in the same conditions. I've towed a 25' travel trailer with an empty weight of 4450lbs loaded up with all our stuff, bikes etc. and while a long steep hill will really have the truck working to get to the top, it can do it fine. My inlaws owned the Trailblazer before us and towed a 27' travel trailer with an empty weight just shy of 5200lbs, right at the rating for the truck empty. Even with their stuff in the trailer the truck pulled it without hurting anything. Just don't expect to haul something with that much weight and frontal area at 70mph+. Taking your time and going easy is the best way when you are pulling a trailer. I can't recommend towing more than the truck is rated at, my father-in-law did swap it on a Yukon to get a bit of reserve capability for the steep hills for some trips they planned up north.
 

Jkust

Member
Dec 4, 2011
946
Yep I need the full scoop here too. I've towed my two sleds and open trailer many times with my crapy minivan and even it doesn't break a sweat. Thats about 900lbs of sleds one is a 2-up Ski Doo and the other a ZR 600 plus whatever a newer 10 foot floe Trailer plus the spare weigh. Everything on the minivan is inferior to an i6 TB.
 

million-miles

Member
Jan 10, 2012
189
ok im missing something. Your running z71's. is that z71 tires rims what? yes im a lot lost on that term. If you increased your overall tire diameter then your going to notice a diff without regearing.
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
I think there is something that you are missing to tell us here. The Z71 springs will only help you from sagging the rear end so much, they do not increase performance or capacity. So lets totally take the Z71 springs out of the picture here.

I know you have a 3.42 rear end and want to do a lift running 31" tires. What tires are you running right now? Tell us everything about your towing setup as far as trailer and all of the gear you carry. Take a picture of your trailer behind the TB is even better.
 

bigytwotone

Member
Dec 7, 2011
489
Dawson creek BC Canada
Ok i don't know what is so wrong with you truck i have the same setup i have the 4.2l and the 3.42 gears and my truck tow's like a champ my mothers truck died ones and i had to tow her 30ft travel trailer with a total weight of 5800 LBS and I had no problems with it so i don't know whats wrong with your truck to do so poorly can you put a pic up to see what it is siting like with the trailer on it??
 

IslandRunner

Member
Dec 4, 2011
316
I towed stuff that weighed as much as my truck when I was stock(bad Idea) but other than wearing out the tranny I had no issues with pull the weight.
 

03envoy

Original poster
Member
Dec 25, 2011
537
djthumper said:
I think there is something that you are missing to tell us here. The Z71 springs will only help you from sagging the rear end so much, they do not increase performance or capacity. So lets totally take the Z71 springs out of the picture here.

I know you have a 3.42 rear end and want to do a lift running 31" tires. What tires are you running right now? Tell us everything about your towing setup as far as trailer and all of the gear you carry. Take a picture of your trailer behind the TB is even better.

Yes, I don't have a pic. Also, nothing special just about 50% tread Michelin tires. Idk what kind (forgot) but, they are regular street tires. Until I get my 31's. But combined weight with trailer is 1200lbs. It's not enclosed. It's open, but I towed anywhere from 65 to 75 and it just didn't matter what speed I was at it didn't want to go. This vechical is in amazing condition with only 115,000 miles and never towed a thing. I had about 150 to 200lbs of Gear and tools in back seat also. I just didn't understand. My dads Traverse, Longer wheels base than Envoy I beleive, Tows like they aren't there. Is it the inline 6 that is just not great for towing compared to a v6? Sorry for my noobishness:redface:
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
03envoy said:
Yes, I don't have a pic. Also, nothing special just about 50% tread Michelin tires. Idk what kind (forgot) but, they are regular street tires. Until I get my 31's. But combined weight with trailer is 1200lbs. It's not enclosed. It's open, but I towed anywhere from 65 to 75 and it just didn't matter what speed I was at it didn't want to go. This vechical is in amazing condition with only 115,000 miles and never towed a thing. I had about 150 to 200lbs of Gear and tools in back seat also. I just didn't understand. My dads Traverse, Longer wheels base than Envoy I beleive, Tows like they aren't there. Is it the inline 6 that is just not great for towing compared to a v6? Sorry for my noobishness:redface:

yours puts out 270 HP, you may have something else that is giving you the problems. Have you done the 100K services and tuneup?
 

IslandRunner

Member
Dec 4, 2011
316
03envoy said:
Yes, I don't have a pic. But combined weight with trailer is 1200lbs. It's not enclosed. It's open, but I towed anywhere from 65 to 75 and it just didn't matter what speed I was at it didn't want to go. This vechical is in amazing condition with only 115,000 miles and never towed a thing. I had about 150 to 200lbs of Gear and tools in back seat also. I just didn't understand. My dads Traverse, Longer wheels base than Envoy I beleive, Tows like they aren't there. Is it the inline 6 that is just not great for towing compared to a v6? Sorry for my noobishness:redface:

The I6 and more HP and Torque than the V6 so it's not the engine.

2002-2005 4.2I6 vortec 4200 LL8 270hp- 275lb ft
2006-2009 4.2I6 Vortec 4200 LL8 290hp- 277lb ft

1996–2004 4.3 L Vortec 4300, SEFI 180 hp–190 hp 245 l b ft
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
IslandRunner said:
The I6 and more HP and Torque than the V6 so it's not the engine.

2002-2005 4.2I6 vortec 4200 LL8 270hp- 275lb ft
2006-2009 4.2I6 Vortec 4200 LL8 290hp- 277lb ft

1996–2004 4.3 L Vortec 4300, SEFI 180 hp–190 hp 245 l b ft

In the traverse it is something like 282hp and I think 258 lb ft
 

03envoy

Original poster
Member
Dec 25, 2011
537
Changed plugs, routine oil change. I mean what else? I am still learning about services and such. But I know my way around cars. So like tranny oil change? I am doing differential soon also. Thanks
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
djthumper said:
yours puts out 270 HP, you may have something else that is giving you the problems. Have you done the 100K services and tuneup?



:iagree:

Also sounds like it could be a partially plugged cat.
 

03envoy

Original poster
Member
Dec 25, 2011
537
Wooluf1952 said:
:iagree:

Also sounds like it could be a partially plugged cat.

What Makes you say that? Symtoms? What are they? Because Imwas going to switch to flow master and I can change cat also?:confused:
 

Jkust

Member
Dec 4, 2011
946
Why don't you tell us exactly what is happening and when.
 

03envoy

Original poster
Member
Dec 25, 2011
537
What do you want to know? When I am towing trailers sleds, Uhaul, etc. My truck really has trouble getting to good speed (on highway) and taking off (in city) . Which now that I think about it, I got about 12mpg which doesn't, Bother me, but a clogged or partially clogged cat could cause this issue with restricted exhaust output.....?
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
03envoy said:
What do you want to know? When I am towing trailers sleds, Uhaul, etc. My truck really has trouble getting to good speed (on highway) and taking off (in city) . Which now that I think about it, I got about 12mpg which doesn't, Bother me, but a clogged or partially clogged cat could cause this issue with restricted exhaust output.....?

Maybe we don't exactly understand what you are saying about the good speed and taking off in the city. I have hauled around 3000 LBS with mine lifted with 3.42 rear end and don't have too much of a problem until I start hitting some of the steeper hills. There is a possibility that you have a partially clogged cat causing you to lose power.
 

Jkust

Member
Dec 4, 2011
946
Just brainstoriming here but I learned that a blinking check engine light means unburned fuel getting in the cat converter and damaging it. Have you ever had any blinking check engine lights over the years?
Also, does it perform normal when not towing?
Also, does Michigan require emissions testing? What did the last test show?
 

gmcman

Member
Dec 12, 2011
4,656
To add to what others have said, what condition is your air filter in? Cruising around with no trailer a dirty air filter doesn't make too much of a difference, but when you need power it really hogs it down. Just something to check.
 

03envoy

Original poster
Member
Dec 25, 2011
537
Jkust said:
Just brainstoriming here but I learned that a blinking check engine light means unburned fuel getting in the cat converter and damaging it. Have you ever had any blinking check engine lights over the years?
Also, does it perform normal when not towing?
Also, does Michigan require emissions testing? What did the last test show?

No lights. Yes, performs well. And No Michigan doesn't. I have a K & N air filter will try and post pic. Not very dirty I don't think.
 

03envoy

Original poster
Member
Dec 25, 2011
537
I dont know how or where to test Cat. But here ares some pics of the filter....View attachment 17992

Edit: Just sent K and N a Email requesting a new filter. Its getting Pretty old....
 

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The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
03envoy said:
I dont know how or where to test Cat.
You pull the upstream O2 sensor out of the exhaust manifold and install a backpressure gauge, or pay a muffler shop to do it. Did you change the O2 sensor at 100K when you put in (I assume) Delco 41-103 plugs?
But here ares some pics of the filter....
Edit: Just sent K and N a Email requesting a new filter. Its getting Pretty old....
It may be old, but it's horribly dirty. Throw in a paper one as a test. Have you ever use the K&N cleaning and re-oiling kit on it? Why would you buy a new one straight from K&N - they have them at all my local parts stores? Except with desert dust I got rid of my K&N as soon as I did the research about the small particles they allow through.
 

03envoy

Original poster
Member
Dec 25, 2011
537
the roadie said:
You pull the upstream O2 sensor out of the exhaust manifold and install a backpressure gauge, or pay a muffler shop to do it. Did you change the O2 sensor at 100K when you put in (I assume) Delco 41-103 plugs?It may be old, but it's horribly dirty. Throw in a paper one as a test. Have you ever use the K&N cleaning and re-oiling kit on it? Why would you buy a new one straight from K&N - they have them at all my local parts stores? Except with desert dust I got rid of my K&N as soon as I did the research about the small particles they allow through.

I didnt replace the O2 sensor, Where can I get one? Local Auto store? I applied for a warranty for K & N. I didnt buy one. But If I do it will be a green air filter. Thanks Roadie
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
03envoy said:
I didnt replace the O2 sensor, Where can I get one? Local Auto store?
Yes. ONLY use AC Delco. Other brands have been reported to have a slight issue with the heater circuit and they throw a code even if they work OK otherwise. You may find this a frustrating project if it's never been changed before. You may want to get help.
I applied for a warranty for K & N.
Huh? Getting filthy isn't a warranty issue, is it?
 

03envoy

Original poster
Member
Dec 25, 2011
537
the roadie said:
Yes. ONLY use AC Delco. Other brands have been reported to have a slight issue with the heater circuit and they throw a code even if they work OK otherwise. You may find this a frustrating project if it's never been changed before. You may want to get help. Huh? Getting filthy isn't a warranty issue, is it?

No, But i figured Id give it a try? why not??lol:crazy:

Thanks, Its never been changed.
So I am looking at:

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_x_10031763-P_x_x
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
03envoy said:
No, But i figured Id give it a try? why not??lol:crazy:
Because it's a waste of everybody's time to ask silly questions you should already know the answer to?
Thanks, Its never been changed.
Oh, may I PUHLLLLLEZE let the old Roadie out of his cage to answer this? :rotfl:

I suppose for the sake of the vehicle I better ask, did you change the transfer case fluid every 50K miles religiously? :confused:
 

03envoy

Original poster
Member
Dec 25, 2011
537
the roadie said:
Because it's a waste of everybody's time to ask silly questions you should already know the answer to? Oh, may I PUHLLLLLEZE let the old Roadie out of his cage to answer this? :rotfl:

I suppose for the sake of the vehicle I better ask, did you change the transfer case fluid every 50K miles religiously? :confused:



Just got vechical at 115,000 miles, I beleive so Mr.Roadie.:biggrin:
 

Chickenhawk

Member
Dec 6, 2011
782
I will put money on the fact that your cat is partially clogged, as the others have said.

Take it for an easy and cheap exhaust backpressure test. They will test it at idle and at 2500 RPM. Write down the readings, and let us know what they are.

Then, start worrying about maintenance that has probably never been done.
 

03envoy

Original poster
Member
Dec 25, 2011
537
Chickenhawk said:
I will put money on the fact that your cat is partially clogged, as the others have said.

Take it for an easy and cheap exhaust backpressure test. They will test it at idle and at 2500 RPM. Write down the readings, and let us know what they are.

Then, start worrying about maintenance that has probably never been done.


Hopefully I will be able to make it over there sometime soon but, When I do I will let you know thanks!
 

03envoy

Original poster
Member
Dec 25, 2011
537
Tried towing again this week with the air filter cleaned. WOW what a difference it doesnt hesitate or struggle and it seems to handle them quiet well! Thanks for everybodies help! It happened to be an error on my part rather than the Trucks. Thanks Again!:crazy:
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
03envoy said:
Tried towing again this week with the air filter cleaned. WOW what a difference it doesnt hesitate or struggle and it seems to handle them quiet well! Thanks for everybodies help! It happened to be an error on my part rather than the Trucks. Thanks Again!:crazy:

Yet another successful repair
of the loose nut behind the wheel
. :thumbsup:
 

mnypitTBEXT

Member
Jan 29, 2012
133
03envoy said:
Tried towing again this week with the air filter cleaned. WOW what a difference it doesnt hesitate or struggle and it seems to handle them quiet well! Thanks for everybodies help! It happened to be an error on my part rather than the Trucks. Thanks Again!:crazy:

Yeah, I was thinking you needed to fix that first. We used to tow a double jetski trailer with my wife's honda Del Sol and my Triumph TR8(back in 1996), so you shouldnt have any issue towing a couple sleds with an Envoy.
 

03envoy

Original poster
Member
Dec 25, 2011
537
If I was to get a Transmission cooler, Do you guys think it would be a issue in the winter with below freezing temps and possibly in the negatives? I would be towing a two place sled trailer one enclosed one not, with two sleds. Approximatly 1500lbs.

Would the Efans help in a situation like this?Thanks
 

Mark20

Member
Dec 6, 2011
1,630
I'm not sure if Evans would make a difference but you could always put a piece of cardboard over the tranny cooler to allow the tyranny to come up to temperature.
 

03envoy

Original poster
Member
Dec 25, 2011
537
Yea, I could do that but prefer not to. I just wondered if it would benefit me rightnow. Once I start towing my 5,000lb trailer in a couple years up north then I will most likly need one. The Efans may help in the city though.... Just some thoughts.
 

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